Most modern vehicles include a variety of safety systems designed to alert driver or other occupants to operational or environmental conditions that can pose a risk to vehicle occupants. Conventional vehicle safety systems may include, for example, forward or rear collision warning systems, land departure warning systems, and side and rear object detection systems among others. When a safety system detects a condition that creates a risk to the vehicle and/or its occupants, a signal is generated and that signal is translated into an alert to the driver and/or other occupants by a warning system. The warning system may comprise an audio device that generates a sound (e.g., a beep or chime) or message. Alternatively, the warning system may comprise a haptic actuator that generates a vibration felt by a vehicle occupant through, for example, a vehicle seat.
Existing systems for providing audio alerts to vehicle occupants have drawbacks. Vehicle occupants can find audio alerts annoying leading to consumer dissatisfaction and the disabling of safety systems; thereby reducing the potential safety benefits. Audio alerts may also be ineffective for hearing-impaired occupants. Haptic alerts overcome some of the drawbacks of audio alerts and have been found to better communicate the location of the risk to the vehicle and/or its occupants (e.g., vibrating the front, back, left or right of the driver's seat bottom), since it can be difficult to localize a sound in a reverberant in-cab environment. Haptic alerts are, however, relatively complex and can add significant cost and complexity to the vehicle.